Cartridge-type fuse



E. C. BALLNIAN. CARTRIDGE TYPE FUSE. APPLicATloN FILED N0v.15,1918.

Patented Aug. 17, 1920.

llllill Ill EN t i l F N f.

\\\ llllllMlllllllI/IIIIIIA UNITED STATES PATENT OFFICE.

EDWIN C. BALLMAN, 0F ST. LOUIS, MISSOURI, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, T0 VALLEY ELECTRIC COMPANY, 0F WILMINGTON, DELA- WARE, A CORPORATION OF DELAWARE.

CARTRIDGE-TYPE FUSE.

Application led November 15, 1918.

To all whom 'it may concern:

Be it known that I, EDWIN C. BALLMAN, a citizen of the United States, and residing at St. Louis, Missouri, have invented the new and useful Improvement in Cartridge-Type Fuses, of which the following is a specification.

llhis invention relates to electric uses, and more particularly to fuses of the cartridge type.

One of the objects of this invention is to provide an electric fuse which Will not only extinguish the arc formed upon rupture of the fuse-link, but which Will also intimate the condition of the fuse-link, as well as the character of the current flow which caused the rupture of the fuse-link.

Further objects will appear from the detail description taken in connection with the accompanying drawing, in which,

Figure 1 is a cross section of a fuse embodying this invention;

Fig. 2 is asimilar view showing the condition when the fuse-link is ruptured by an overload current; and,

Fig. 3 is a view similar to Fig. l, showing the condition when the fuse-link is ruptured by a short-circuited current.,

Referring to the accompanying drawing, l designates a case which may be of fiber, a paper impregnated with sodium-silicate, or other tire-proofing compound, or any other suitable insulating material. Connected to the ends of the case are terminal caps 2 of any suitable metal, and connecting these caps is a fuse-link or wire 3, which may be of any suitable fuse-link metal having the necessary low melting point.

Mounted on the fuse-link 3 and within the case is a tubular element 4 which may be made of any suitable insulating and fireproof material, such as clay, porcelain, glass, or of the same material as the case 1 is made of. This tubular element is open ended, of a length less than the length of the case, and lwhile the connection is such that the tubular element is loose on the fuse-link, so that this element will slide freely on the link, the connection is not so loose that this element will rattle when the case is given a sidewise vibration. The interior of the tubular element is provided with corrugations or projections 5, or the interior is simply roughened or left unglazed when paper, porcelain Specification of Letters Patent.

Patented Aug. 17, 1920. Serial No. 262,696.

or clay is used, for a purpose hereinafter to be described.

When the fuse is in good condition with the fuse-link unruptured, lthe tubular element is slidable endwise on the fuse-link, but will not rattle if the casevis given a sidewise vibration. lVhen, however, the ordinary overload current traverses the fuselink, thereby causing it to slowly melt at some point within the tube 4, this being the hottest part, the fuse-link will rupture, as shown in Fig. 2, but the molten metal of the fuse-link will :flow into and between the interstices between the projections 5, or into the pores of thc unglazed inner surface of the tubular element, thereby adhering thereto. This will cause the tubular element to adhere to and be removably retained by the fuse-link, so that if the case is shaken either endwise or sidewise, no rattling can be heard. This condition is clearly shown in F ig. 2. If, however, the fuse is blown under short-circuit conditions, the arc which is formed in the tubular element 4, causes a very rapid expansion of gases inside of this element, which blows out the arc that is formed, thereby giving a better means of suppressing the arc than when the case is filled with an inert porous substance, as in the present fuses. Moreover, this rapid eX- lpansion of the gases inside of the tubular element blows the molten metal endwise out of the tube and against the ends of the case, as shown in Fig. 3, thereby completely freeing the tubular element. When, therefore,

the case is shaken either endwise or sidewise,

the tubular element will rattle in the case It will, therefore, be seen that this invention accomplishes its objects. Not only is the arc vcaused by the rupturing of the fuselink under lshort-circuit conditions comruptured under ordinary overload conditions, then it will not rattle at all either upon endwise or sidewise vibration of the case. 'lt the fuse-link has heen ruptured under short-circuit conditions, then the tubular element will rattle both upon endwise and sidewise movements of the case.

lt is obvious that various changes may be made in the details Without departing from the spirit ot this invention. tore, to he understood that this invention is not to he limited to the specilic construction shown and described.

Having` thus described the invention, what isA claimed is:

l. in electric fuse, comprising, a case, terminals on said case, a fuse-link connectingsaid terminals, and anelement mounted on said fuse-link, adapted to intimate the condition of said :fuse-link.

2. rin electric ifuse, comprising, a case, terminals on said case, a 'fuse-link connecting said terminals, and an element mounted on said 'fuse-link, adapted to intimate the character olf thecurrent flow which caused rupture 'of said. u'se-linlr.

3. rin electric Jfuse, comprising, a case, terminals on said case, a fuse-link connecting` said termina-ls, and a freely movable, tubular element mounted on said fuse-link.

d. in electric fuse, comprising, a ease, terminals on said case, a Jfuse-link connectsaid terminals, and tubular element mounted on said fuse-link hut free 'from Contact with said case.

5. ein electric fuse, comprising, a case, terminals on said case, a fuse-link connecting said terminals, and a freely movable,

lt is, there- Y a 'freely movable,

tubular, open ended element mounted on said fuse-link. i

6. An electric fuse, comprising, a case, terminals on said case, a fuse-link connecting said terminals, and a freely movable,

- tubular, open ended element of a length less than the length of said case and mounted on said fuse-link.

7. 2in' electric inse, comprising, a case, terminals on said -case, a fuse-link connecting said terminals, and a freely movable, tubular element mounted on said fuse-link and adapted to canse adherence thereto ot the ruptured fuse-link.

,8. An electric fuse, comprising, a case, terminals on said case, a inse-link connecting said terminals, and a. tubular open ended element adapted to slide 'freely on said taselinlr.

9. An electric terminals on said case, ing; said terminals, and a tubular open ended element adapted to slide freely on said fuseiink lont 'free from Contact With said case,

10. flnrelectii-c use, comprising, a case, terminals von said case, a fuse-link connecting said terminals, and a tubular open ended element adapted to. slide freely en said inselinlr hut 'tree from contact with. saidv case and adapted to cause adherence thereto oi the ruptured'fuse-link. p u Y ln testimony whereof l ailix my signature this 7 th layof May, 191,8.

a fuse-link connect- A' EDWIN C. BALLlV AN.

fuse, comprising, a case, 

